He mentioned to me that the idea of separate pots for meat and dairy is a later policy and is not rooted in Talmudic Law. IOW a poor family could continually kasher a pot back and forth , or for S'phardim rely on Na"t bar Na"T to use a day old pot l'chatchilah.
I'm not sure of the precise logistics re: using a day old pot.
He also said that since glass does not absorbed it is inherently Pareve and could "swing both ways" [my words NOT his]
Thus it appears that "separate dishes" is not an absolute Halachic requirement but a Policy
Note: I prefaced our discussion with a general observation that about 80% of what we do is Post-Talmudic. Of course this was "guzma" because I never actually went through everything we do, but things like Qaddish, the nusach hat'fillah etc. [Not the foundational principles] really coalesced in Gaonic times.